In the context of integrated circuits, it may be desirable to implement low power transistors having low leakage currents. However, current transistor designs and implementations may have substantial limitations. For example, metal-oxide-semiconductor field-effect transistors (MOSFETs) have a sub-threshold slope with a theoretical limit of kT/q (e.g., such that k is the Boltzmann constant, T is temperature, and q is the elementary charge). At room temperature, for example, the theoretical limit of the sub-threshold slope (SS) may be 60 mV/dec (millivolts per decade) for MOSFETs.
In particular, for a leakage current target, which may determine an integrated circuit's standby power requirement, a MOSFET may only increase at a maximum rate of kT/q (e.g., 60 mV/dec at room temperature) from the leakage current target to the MOSFET's on-current. Furthermore, for low active power, the integrated circuit may be required to operate at lower supply voltages. However, due to the limited (e.g., kT/q) rate of increase of current from leakage current to on-current, when a MOSFET is operated at low supply voltages, the on-current (and therefore performance) is significantly reduced because it may be operating close to its threshold voltage.
In other implementations, tunneling field-effect transistors (TFETs) may be implemented. Such TFETs may achieve sharper turn-on behavior (e.g., a lower sub-threshold slope than MOSFETs), which may enable higher on-currents than MOSFETs at lower supply voltages. However, to attain such TFET characteristics, a variety of materials and/or manufacturing advancements may be needed, such as developing exotic channel materials, attaining low defect density oxides on such exotic channel materials, and/or manufacturing thin transistor bodies using such exotic materials.
As such, existing technologies do not provide low power transistors having high performance and low leakage currents. Furthermore, replacement technologies such as TFETs may require significant development efforts due to novel material requirements. Such problems may become critical in low power integrated circuit implementations.